This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Currently, there is a significant need for more therapeutic agents for the treatment of neuropathic pain. We propose to use painful diabetic peripheral neuropathy (DPN) patients to study the efficacy of inhaled cannabis on neuropathic pain. We will enroll 20 subjects with each subject acting as their own control (receiving both placebo and three doses of inhaled cannabis (low, medium and high) in random order each separated by at least two weeks. HYPOTHESES: 1) Cannabis will result in a dose dependent decrease in the spontaneous pain and qualitative pain descriptors. 2) Pain relief will occur at cannabis doses that do not significantly affect cognitive function. 3) Cannabis will decrease experimental pain as measured by the BTS. The effect on the BTS will correlate with the decrease in spontaneous pain of DPN.